Drainage apparatus for movable roofs



Sept. 6, 1955 M. w. GABLE DRAINAGE APPARATUS FOR MOVABLE ROOF'S 3 Sheets-Sheet 1 Filed July 18. 1949 lnveni'or: M ron \N. Gable hxs A++ornau Sept. 6, 1955 M. w. GABLE DRAINAGE APPARATUS FOR MOVABLE ROOFS 3 Sheets-Sheet 2 Filed July 18, 1949 gron W. 60MB his A++orneg Sept. 6, 1955 M. w. GABLE DRAINAGE APPARATUS FOR MOVABLE ROOFS I5 Sheets-Sheet I5 Filed July 18, 1949 lnven+or= Mgr-on W. Gabte his AH'orneL5 United States Patent'O 2,717,095 I DRAINAGE APPARATUS FOR MOVABLE ROOFS Myron W. Gable, Houston, Tex., assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware Application July 18, 1949, Serial No. 105,413

9 Claims. (Cl. 220-26) This invention relates to drains for conducting water from the vertically movable roof of a storage tank through the interior of the tank to a stationarypipe near the bottom, through which the water can be discharged to the exterior of the tank. The invention is particularly, although not specifically, useful for draining rain water from floating roofs.

There is a general class of roofs, known .as movable roofs, which may be constructed according to any of various designs, such as pontoon roofs, double-decked roofs, pan type roofs, etc., wherein the roof floats on the liquid stored within the tank, rising and falling in accordance with the liquid level therein, or mechanically supported movable roofs. Such roofs are used to store petroleum products, such as crude oil, gasoline,'lubricating oil, as well as other liquids. When the nature of the stored liquid is such that water can safely be permitted.

to settle through it to form a water layer rain water is often drained from the roof by a siphon drain. When it roof descend to the tank bottom. Such hose, when empty, will float to the surface to form air pockets which would interfere with free drainage. Further, long lengths of hose are expensive'to replace when attacked by the stored liquid. Articulated drain pipes have also pre sented operating and maintenance difficulties: If the joints are too tight they will bind and the long lengths of pipe (commonly 30 to 40 feet in length) will often buckle and collapse; if they are too loose they leak and either admit water into the stored liquid or permit stored liquid to enter the drain. Later developments incorporated elaborate ground or packed joints, which, are expensive and still require frequent maintenance and careful adjustment. I

It is an object of the present invention to provide an improved articulated drain apparatus for movable-roofs of storage tanks which is reliable in its operation and inexpensive to construct and which can be easily adjusted.

A further object of the invention is to provide improved drain of the type described wherein two flexibl e elements 'are'provided at the joints, one for carrying the structural load and the other for conducting the water, whereby the structural load can be carried by freely movable hinged structural joints and the" eflectiveness of the liquid seal between the sections of the drain do not depend upon the tightness of the structural joints.

Still another object is to provide an'irnproved drain of the articulated type wherein at least one end of the drain (either the top or the bottom) is movable horizontally as the roof rises or falls. and the horizontally movable end is connected to a horizontally non-movable fitting by a short section of flexible hose.

In summary, the down drain comprises a plurality of two or more sections or rigid drain pipe, articulated at their junctures by compound joints comprising (1) a structural hinge for transmitting mechanical stress, and (2) an independent flexible liquid connection in the form of a short section of flexible conduit, such as hose, arranged to interconnect the conjoined sections. Such a drain is conveniently pivotally connected either at the top or bottom to the movable roof or to the tank bottom, as the case may be, by a similar compound joint, while the end which is not so pivotally connected is movable v which consist of a single pipe pivotally connected at one end, either to the movable roof or to the tank bottom (see Fig. 5 of U. S. Patent No. 1,761,700) e. g., by the compound joint, the laterally movable end of the drain pipe is connected to a drain fitting (which may be either the sump in thereof, or the stationary discharge pipe at the tank bottom) by a short section of flexible con duit, such as a hose. In the preferred embodiment the laterally movable end of the drain is guided for linear motion by a track and the fitting is disposed some distance to the side of the line of travel of the end of the drain. The flexible hose therefore extends laterally from the end of the drain. While the flexible conduitmay be fitted to the side of the drain it is preferable to arrange it to fit it to extend from the drain end first generally in the line of travel of the drain end and then to make a bend of approximately a right angle, being either curved continuously or provided with an L-fitting' intermediate its ends; by this preferred arrangement the possibility of pinching the hose between the drain and its track or the tank bottom is obviated. t

The invention will be described in greater detail by reference to the'accompanying drawings forming a part of this specification and showing certain preferred embodiments by way of illustration, wherein:

Fig. 1 is a fragmentary vertical sectional view of a floating roof storage tank equipped with the improved drain;

Fig. 2 is a fragmentary plan view of the tank bottom; Figs. 3 and 4 are enlarged detail of parts as seen from lines 33 and 44, respectively, indicated on Fig. 1; Fig. 5 is an enlarged sectional view through a joint,

taken on section line 55 of Fig. 1;

Fig. 6 is a fragmentary vertical sectional view of a storage tank showing a modified embodiment; 1 Fig. 7 is a sectional view taken on line 77 on Fig. 6

Referring to the drawings in detail, 10 indicates the cylindrical, upright wall of a storage tank containing a roof 11 floated on the stored liquid by any conventional means (not shown) and sealed to the tank wall by a running seal 12. The roof may be inclined downwardly toward itscenter and there provided with a drain opening in the form of a drain sump 13 with a perforated cover or sieve' 14. 15 indicates a stationary dischargepipe which extends into and terminates within the tank near the bottom thereof. The parts thus far described are known and may be in accordance with any desired design. I

The articulated down drain comprises two section s of rigid drain pipe indicated at 16 and 17 having a compound joint as shown in Figs. 1, 3 and 5. The structural or stress-transmitting part of the joint comprises a' pair of invention, which angles 18' welded to the sides of the pipe 16 near its lower end to form bifurcations extending beyond the pipe and supporting a horizontal journal 19. A Y-fitting 20 is rigidly coupled to the upper end of the lower pipe 17 and coupled to laterally spaced, parallel branches 21, both in flow communication with the pipe 17. Vertical support plates 22, having vertical stiffening ribs 22a, are welded to the branches 21 and are apertured to form bearings through which the journal 19 extends. The drain sections 16 and 17 are thereby given a pivotal connection about the axis of journal 19. The liquid carrying part of the joint comprises a short section of flexible hose 23 removably connected to the lower end of the upper pipe 16 by a coupling 24, and to the lower pipe 17 by a coupling 25 rigidly fixed to a T-fitting 26 which is interposed between the branches 21. It is evident that water can flow from pipe 16 through the hose 23, T'- fitting 26, both branches 21, and Y-fitting 20 into the pipe 17, and that the hose will flex when angular motion between the pipes occurs. As shown in Fig. 1, the T-fitting 26 is turned slightly up from the plane of the branches 21 to reduce the maximum flexure of the hose.

The upper end of the pipe 16 is provided with a pair of angles 27 carrying a transverse journal 28 having rotary motion in depending bracket plates 29 which are carried by the roof, these parts being arranged in the manner previously described for parts 18, 19 and 22, respectively, to form a pivoted structural support. A short section of flexible hose 30 is removably connected to the pipe 16 by a coupling 31 and to the sump 13 by a coupling 32.

The joint between the pipe sections is supported from the roof by a chain 33 which is divided near its lower end into diverging branches 33a and 33b and thereby connected to the ends of a transverse bar 34 which is welded to the bottom of the branches 21. A horizontal axle 35 is welded to the bottom of the branches 21 and carries rotatably thereon a pair of wheels 36. It will be understood that these wheels engage the tank bottom when the roof has descended through approximately half of the height shown in solid lines in Fig. 1.

As shown in Figs. 1 and 4, a pair of angles 37 are welded to the sides of the pipe 17 at its lower end to form bifurcations extending beyond the pipe and connected to a horizontal axle 38 rotatably supporting a pair of wheels 39, which are connected as shown in Fig. for the wheels 36. The axle 38 is bowed upwardly to above the axis of the pipe 17 as indicated at 38a. A pair of angles 40 are optionally fixed to the tank bottom to form a guide track. These tracks are preferably spaced apart farther than the gauge of the wheels, as shown, so that they are not normally engaged thereby and serve to prevent any appreciable deviation of the line of travel of the end of the pipe from a straight line.

A flexible hose 41 is removably connected to the lower end of the pipe 17 and to the drain fitting by couplings 42 and 43, respectively. The hose 41 passes beneath the bowed portion 38a and makes a continuous right angle bend; it is of sufiicient length to permit movement of the end of the pipe 17. The position of the hose when the pipe 17 is retracted to the left as seen in Figs. 2 and 4 is shown in solid lines, and its position when the pipe is at its extreme forward position is shown in dotted lines.

In operation, when the roof is near the top of the tank the parts are in the position shown in solid lines in Figs. 1 and 2. As the roof descends the upper section 16 at first remains stationary with respect to the roof, being suspended by the chain 33; the lower end of the pipe 17, therefore, at first moves toward the right on its wheels 39 along a predetermined straight path between the track angles 40. When the wheels 36 touch the tank bottom the lower end of pipe 17 is at its extreme right position, as indicated in dotted lines in Fig. 4. Continued downward movement of the root causes the chain to become slack and the upper section 16 pivots toward a horizontal position about the journals 19 and 28. The

position of the pipes when the roof has almost reached bottom is shownin Fig. l in dotted lines; when the roof is fully lowered the pipes 16 and 17 are parallel and horizontal. During the descent of the roof after the wheels 36 touch the tank bottom the pipe 17 moves on the wheels 36 and 39 toward the left.

It is evident that the short. hose sections 23 and 30 undergo but little flexure and carry no structural stresses during the foregoing operations. Being short, they are readily kept in their proper positions, and are not apt to kink. They can be easily replaced. The structural connections about the journals 19 and- 28 can be loose so as to otter only a negligible resistance and by spacing the support plates 22 and 29 laterally from the axis of the pipe the drain ismade sturdy and is not likely to buckle.

The hose section 41, if containing water, normally slides along the tank bottom during the horizontalmovement of the end of the pipe 17; however, if empty, or if the stored liquid is denser than water it may float. A staple 44 may be fixed to the tank'bottom to prevent flotation of the hose. This hose undergoes relatively little flexure and the part near the coupling 42 will, by its stiffness, extend in prolongation of the pipe 17, whereby kinking and pinching beneath the wheels 39 are avoided.

According to the modified construction indicated in Figs. 6-7, wherein corresponding parts bear the same reference numbers as in the previously considered figures, the articulated down drain comprises pipes 16 and 17 connected by a compound joint like that previously described, except that the axle 35' and wheels 36 are omitted.

The pipe 17 is mounted for rotation about a fixed hori-- zontal journal 50 at the tank bottom, and the upper end of the pipe 16 is horizontally movable. The journal 50 is mounted in spaced upright brackets 51 and a pair of angles 52 are welded to the sides of the pipe 17 and journalled on part 50. A short length of flexible hose- 53 is removably connected to the pipe 17 and the discharge pipe 15 by couplings 54 and 55.

A shelf 56 is suspended from the roof 11 and is disposed laterally with respect to the sump 13. A pair of angles 57 are also" suspended at one end of'the shelf to form a track the axis of which lies in the plane of'the drain pipes 1617. A pair of angles 58 are welded to the sides at the upper end of the pipe 16 to form bifurcations extending beyond the pipe and carry ahorizontal axle 59 on which wheels 60 are rotatably mounted to ride on the horizontal portions of the angles 57. Flexible hose 61 is removably connected to the upper end of pipe 16 and to the sump 13 by couplings 62 and 63, respectively; it carries an L-fitting 64 intermediate its ends,

and normally rests on the shelf 56 when filled with water. When the hose is empty or when the stored liquid has a high specific gravity, the hose will float in engagement with the under side of the roof 11.

In operation, the drain assumes the position indicated in solid lines in Figs. 6 and 7 when the roof is at the top. As the roof descends two phases should be distinguished: During the first phase the lower pipe 17' r0 tates downwardly about the journal 50, thereby moving the joint between the pipes downwardly and to the left (as seen in Figs. 6 and 7). The wheels 61 roll toward the left along the track angles 57, and the hose 61 slides along the shelf to the dotted line position indicated in Fig. 7. During this first phase of the movement the upper pipe 16 undergoes only a slight change in angle with respect to the roof, so as to permit its lower end to swing through an arc aboutthe point of attachment of the chain 33 to the roof. When the left end of the pipe 17 reaches the bottom of the tank the wheels 60 are at their extreme left position. Continued descent of the roof during the second phase causes the pipe 16 to rotate toward the horizontal position, turning on the now stationary pivot journal 19 and. causing the wheels 60 to roll toward the right. When the roof is in its lowermost position the pip'es 16 and 17 are both horizontal.

I claim as my invention:

1. Drainage apparatus for a movable roof of a tank comprising: a drain opening in the roof; a discharge pipe extending into and terminating within the tank below the roof; and an articulated down drain connected to establish flow communication between said drain opening and said discharge pipe and having a plurality of rigid pipe sections connected by one or more compound joints in the tank, each joint comprising: a framework carried by and extending transversely of the first conjoined pipe section and beyond the end thereof; a pair of rigid branch pipes fixed to the end of the second conjoined pipe section in flow communication with said second pipe section and extending longitudinally, one on each side of the axis of the second pipe section; pivotal connections having a common axis between said branch pipes and said framework for transmitting mechanical stress between said pipe sections; a transverse pipe beyond said pivotal connection interconnecting said branch pipes; and a short section of flexible hose connected to the end of the first pipe section and extending thence beyond said hinge axis to said transverse pipe for establishing communication between said pipe sections independently of said pivotal connection.

2. Drainage apparatus for a movable roof of a tank comprising: a drain opening in the roof; a shelf suspended from said roof; a track suspended from said roof adjacent said shelf; a discharge pipe extending into and terminat ing within the tank near the bottom thereof; a movable down drain having its lower end movably connected to the tank bottom and in communication with said discharge pipe and its upper end supported for movement along said track; and a flexible hose on said shelf coupled at one end thereof to the upper end of the down drain and at the other end thereof to said drain opening in the roof.

3. In combination with the drainage apparatus according to claim 2, a transverse axle fixed to said down drain above the point where the flexible hose is coupled to the down drain, said axle having a wheel movable on said track.

4. Drainage apparatus for a movable roof of a tank comprising: a drain sump in said roof; a shelf suspended from said roof and extending to one side of said sump; a pair of parallel tracks suspended from the roof adjacent to said shelf, the center line between said tracks being spaced from said sump; a discharge pipe extending into and terminating within the tank near the bottom thereof; a movable down drain having its lower end movably connected to the tank bottom and in communication with said discharge pipe and having at its upper end a framework extending beyond end and to the sides of the down drain; an axle on said framework beyond the upper end of the down drain; a pair of wheels on said axle movable along said tracks; and a flexible hose on said shelf coupled at one end thereof to the upper end of the down drain extending first substantially horizontally in alignment with said down drain, extending thence between the shelf and the roof substantially through a right angle bend, and coupled at its other end to said drain sump.

5. A swivel joint comprising, in combination: a first pipe; a second pipe having a main part and a forward part, said forward part having an opening facing substantially toward said main part and situated near an end of the first pipe; a pivot support carried by the first pipe near said end thereof; a pivotal connection between said pivot support and said forward part of the second pipe having a pivot axis substantially perpendicular to said pipes for transmitting mechanical stress between the pipes; and a flexible hose connecting said first pipe with said opening in the forward part in the second pipe to establish flow communication between the pipes.

6. A swivel joint comprising, in combination: a first pipe; a second pipe having a main part and a forward part, said forward part having a substantially reverse bend 6 and having an opening directed generally toward said mainpartof the second pipe; a pivotal connection between said first'pipe near an end thereof and the said forward part of the secondpipe having a pivot axis substantially perpendicular to the said pipes for transmitting connecting said end of the first pipe with said opening to establish flow communication between the pipes. p

7. A swivel joint comprising, in combination: a first pipe; a second pipe having an end thereof in proximity tothe first pipe; a pair of pivot supports carried by the first pipe and situated one on each side thereof; a branched pipe structure extending rigidly beyond the said end of the second pipe and in flow communication therewith comprising a pair of side members, situated one on each side of the axis of the second pipe, and an end pipe joining the parts of the side members that are remote from the second pipe; an opening in said end pipe, said first pipe having an opening directed toward and spaced from said opening in the end pipe; pivotal connections between said side members and said pivot supports having a common pivot axis substantially perpendicular to said first and second pipes and between 7 said openings for transmitting mechanical stress between the pipes; and a flexible hose having one end thereof connected to said opening in the first pipe and the other end thereof connected to said opening in the end pipe for placing said first and second pipes into flow communication. 7

8. A swivel joint comprising, in combination: a first pipe; a second pipe lying substantially in the plane of the first pipe and having an end thereof in proximity to an end of the first pipe; a pair of pivot supports carried by the first pipe and situated one on each side thereof and projecting beyond the said end thereof; a branched pipe structure extending rigidly beyond the said end of the second pipe substantially in the plane thereof and in flow communication therewith comprising a pair of parallel side members situated one on each side of the axis of the second pipe and a transverse pipe joining parts of the side members that are remote from the second pipe; an opening in said transverse pipe intermediate the ends thereof directed substantially toward said second pipe, the end of said first pipe having an opening spaced from said opening in the transverse pipe and directed toward said latter opening when the first and second pipes are relatively disposed at an acute angle; a support plate fixed to each of said side members, one plate extending to each of said pivot supports; pivotal connections between said pivot supports and the corresponding support plates having a common pivot axis substantially perpendicular to said common plane of the first and second pipes that lie substantially in the plane of said first pipe between the said openings for transmitting mechanical stress between the pipes; ,and a flexible hose lying substantially in said common plane having one end thereof connected coaxially to the opening in the end of the first pipe and the other end thereof connected to said opening in the transverse pipe for placing said first and second pipes into flow communication.

9. A swivel joint comprising, in combination: a first pipe; a second pipe having an end thereof in proximity to the first pipe; a pair of pivot supports carried by the first pipe and situated one on each side thereof; a branched pipe structure extending rigidly beyond the said end of the second pipe and in flow communication therewith comprising a pair of side members, situated one on each side of the axis of the second pipe, and an end pipe joining the parts of the side members that are i remote from the second pipe; an opening in said end pipe, saidfirst pipe having an opening directed toward;

and spaced. from said opening in the end pipe; pivotal connections. between said side members and said pivot supports having acommon pivot axis substantially perpendicular to said first and second pipes and betweensaid openings for transmitting mechanical stress between the pipes'; a flexible hose having one end thereof connected to said opening inthe first pipe and the other end thereof connected to said opening in the endpipe for placing said first and second pipes into flow communication; an axle fixed to said branched pipe struc ture substantially parallel to said pivot axis; and a pair of wheels on said axle, situated one on each side of said axis of the second pipe, for supporting saidbranched pipe structure rollingly and permitting the first pipe. to. be moved pivotally upwardly.

References Cited in thefile of this patent UNITED STATES PATENTS Philiips. "Jan. 13, Willis, Oct. 9, Holmes Aug. 18, McCandless Dec. 8, Bailey June 3, 'Cushi'ng Aug. 26, Patterson Sept. 2,

Adams Sept. 8, Day May 10, Wiggins Feb. 14, Kramer Nov. 6, 

1. DRAINAGE APPARATUS FOR A MOVABLE ROOF OF A TANK COMPRISING: A DRAIN OPENING IN THE ROOF; A DISCHARGE PIPE EXTENDING INTO AND TERMINATING WITHIN THE TANK BELOW THE ROOF; AND AN ARTICULATED DOWN DRAIN CONNECTED TO ESTABLISH FLOW COMMUNICATION BETWEEN SAID DRAIN OPENING AND SAID DISCHARGE PIPE AND HAVING A PLURALITY OF RIGID PIPE SECTIONS CONNECTED BY ONE OR MORE COMPOUND JOINTS IN THE TANK, EACH JOINT COMPRISING: A FRAMEWORK CARRIED BY AND EXTENDING TRANSVERSELY OF THE FIRST CONJOINED PIPE SECTION AND BEYOND THE END THEREOF; A PAIR OF RIGID BRANCH PIPES FIXED TO THE END OF THE SECOND CONJOINED PIPE SECTION IN FLOW COMMUNICATION WITH SAID SECOND PIPE SECTION AND EXTENDING LONGITUDINALLY, ONE ON EACH SIDE OF THE AXIS OF THE SECOND PIPE SECTION; PIVOTAL CONNECTIONS HAVING A COMMON AXIS BETWEEN SAID BRANCH PIPES AND SAID FRAMEWORK FOR TRANSMITTING MECHANICAL STRESS BETWEEN SAID PIPE SECTIONS; A TRANSVERSE PIPE BEYOND SAID PIVOTAL CONNECTION INTERCONNECTING SAID BRANCH PIPES; AND A SHORT SECTION OF FLEXIBLE HOSE CONNECTED TO THE END OF THE FIRST PIPE SECTION AND EXTENDING THENCE BEYOND SAID HINGE AXIS TO SAID TRANSVERSE PIPE FOR ESTABLISHING COMMUNICATION BETWEEN SAID PIPE SECTION INDEPENDENTLY OF SAID PIVOTAL CONNECTION. 